Obstructed Defecation Syndrome

Obstructed defecation syndrome (abbreviated as ODS, with many synonymous terms) is a major cause of functional constipation (primary constipation), of which it is considered a subtype. It is characterized by difficult and/or incomplete emptying of the rectum with or without an actual reduction in the number of bowel movements per week. Functional constipation is usually defined as infrequent bowel movements and hard stools. In contrast, ODS may occur with frequent bowel movements and even with soft stools, and the colonic transit time may be normal (unlike slow transit constipation).

Definitions

ODS is a loose term, consisting of a constellation of possible symptoms, caused by multiple, complex and poorly understood disorders which may include both functional and organic disorders. Furthermore, many different terms have been used, which appear to refer to the same clinical entity. However, the term does not appear in the ICD-11 and Rome-IV classifications, which both instead refer to "functional defecation disorders". Occasionally some sources inappropriately treat ODS as a synonym of anismus. Although anismus is a major cause of ODS, there are other possible causes.

In 2001 the American Society of Colon and Rectal Surgeons (ASCRS), the Colorectal Surgical Society of Australia,
and the Association of Coloproctology of Great Britain and Ireland published a consensus statement which covered definitions relevant to this topic. A revised consensus statement was published by the ASCRS in 2018. Wherever possible, this article generally follows the definitions and terminology of the 2018 consensus statement, wherein ODS is defined as "a subset of functional constipation in which patients report symptoms of incomplete rectal emptying with or without an actual reduction in the number of bowel movements per week." ODS may or may not co-exist with other functional bowel disorders, such as slow transit constipation or irritable bowel syndrome. Functional constipation is usually defined as infrequent bowel movements and hard stools. In contrast, ODS may occur with frequent bowel movements and even with soft stools, and the colonic transit time may be normal (unlike slow transit constipation). Other authors use the term ODS to refer to defecatory dysfunction in the absence of any pathological findings (that is, a purely functional disorder).

ICD-11

The term "obstructed defecation syndrome" does not appear in ICD-11. However, the following entries are present, as well as separate codes for most of the individual organic lesions listed in this article:

* Functional anorectal disorders: "anorectal disorders which principally present anorectal and defecation complaints without apparent morphological changes of anorectal regions." A note is added: "However, the distinction between organic and functional anorectal disorders may be difficult to make in individual patients."
* Functional defecation disorders: this is listed as a sub-entry of functional anorectal disorders (above). It includes dyssynergic defecation (defined as "paradoxical contraction or inadequate relaxation of the pelvic floor muscles during attempted defecation"), and inadequate defecatory propulsion (defined as "inadequate propulsive forces during attempted defecation"). A note is added: "The patients must satisfy diagnostic criteria for functional constipation."
* Incomplete defecation: this entity (ME07.1) exists as a sub-code of fecal incontinence, with no definition.

Rome-IV

The term "obstructed defecation syndrome" does not appear in the Rome IV classification. However diagnostic criteria for functional defecation disorders are listed. According to Rome-IV, this is defined as "features of impaired evacuation" during repeated attempts to defecate. To qualify for this diagnosis, patients must meet the Rome diagnostic criteria for functional constipation or irritable bowel syndrome with constipation (IBS-C). Furthermore, 2 of the following 3 tests must show abnormal results: balloon expulsion test, anorectal manometry or anal surface electromyography, or imaging (e.g. defecography). Two subcategories exist within the functional defecation disorders category: Inadequate defecatory propulsive (F3a) and Dyssynergic defecation (F3b). These are defined as "Inadequate propulsive forces as measured with manometry with or without inappropriate contraction of the anal sphincter and/or pelvic floor muscles", and "Inappropriate contraction of the pelvic floor as measured with anal surface EMG or manometry with adequate propulsive forces during attempted defecation" respectively. The subcategories F3a and F3b are defined by age- and gender-appropriate normal values for the technique. For all of these Rome-IV diagnoses, diagnostic criteria must have been fulfilled for the last 3 months with symptom onset at least 6 months prior to diagnosis.

Signs and symptoms

There is a constellation of possible symptoms.

* Straining, and attempting to defecate for a long period of time
* Use of, or dependence on, enemas and/or laxatives.
* Self-digitation.
* Posturing (the need to assume "unusual" posture).
* Frequent urge to defecate, and frequent bowel movements/toilet visits, where only fecal pellets may be passed.
* Conversely, there may reduced number of bowel movements per week.
* Abnormal stool texture, which may be anything from watery/loose (overflow diarrhea), to fragmented, very hard or pellet-shaped.
* Sense of incomplete evacuation. even with soft stools.
* Unsuccessful attempts at bowel movements.
* Painful bowel movements.
* Tenesmus.
* Bowel urgency.
* Feeling of occupation or "mass" in the vagina.
* Pelvic heaviness.
* Pelvic pain and cramping.
* Bloating.
* Fecal incontinence, which may occur after defecation.
* Urinary incontinence.
* Poor appetite and early satiety when eating.

Fecal incontinence to gas, liquid, solid stool, or mucus in the presence of obstructed defecation symptoms may indicate occult rectal prolapse (i.e., rectal intussusception), internal/ external anal sphincter dysfunction, or descending perineum syndrome.

Self-digitation (digital help, also termed "splinting"), is the use of the digits (fingers) to apply pressure in order to achieve defecation. Most people recognize the need for digitation as a symptom, and not a treatment. Medical professionals generally do not recommend it, since it may lead to complications and is not very effective, only removing feces in the lower part of the rectum. There are 3 methods: vaginal, perineal and rectal. Gloves are used for hygiene. Vaginal digitation is when the patient presses the posterior (back) wall of the vagina to support it, or to push the rectocele pouch from inside the vagina, which makes the anorectum straight and facilitates defecation. "Milking" pressure can also be applied on the posterior vaginal wall. Perineal digitation is pushing on the perineum, which acts to stimulate the transverse muscles of the perineum causing a reflex rectal contraction of the rectum which helps to evacuate the feces. Rectal digitation is when patients insert a finger into the anus to "hook" out fecal pellets, or to apply pressure to the walls of the anus and/or the rectum, or to support an obstructing anatomical defects such as a sigmoidocele. Possible complications of rectal digitation are injury of the lining of the rectum, such as ulcerations with bleeding and discomfort, and anal fibrosis leading to a stricture.

ODS may be a cause of incomplete evacuation of stool. Normal emptying of rectal contents is 90-100%. Less than 90% evacuation could be defined as incomplete evacuation.

Causes

One review stated that the most common causes of disruption to the defecation cycle are associated with pregnancy and childbirth, gynaecological descent or neurogenic disturbances of the brain-bowel axis.unctional obstructed defecation syndrome"> Patients with obstructed defecation appear to have impaired pelvic floor function.

Specific causes include:
* Anismusunctional obstructed defecation syndrome" /> and pelvic floor dysfunction
* Rectoceleunctional obstructed defecation syndrome" />
* "Rectal invagination" (likely refers to rectal intussusception)unctional obstructed defecation syndrome" />
* Internal anal sphincter hypertonia
* Anal stenosis
* Fecal impaction
* Rectal or anal cancer
* Descending perineum syndrome

Dyssynergic defecation (anismus)

Dyssynergic defecation (anismus) is defined as "failure of striated muscles of the pelvic floor (the puborectalis muscle and the external anal sphincter) to relax appropriately during attempted defecation". In extreme cases, when defecation is attempted, the muscles may contract instead of relaxing (paradoxical contraction). Dyssynergic defecation may occur in up to 40% of all patients with constipation.

"Celes"

The suffix ‘-cele’ is from ancient Greek, and means ‘tumor,’ ‘hernia,’ ‘swelling,’ or ‘cavity.’ More modern translations are ‘cystic cavity’ or ‘cystic protrusion.’ A cul-de-sac hernia ( peritoneocele) is a herniation (protrusion) of peritoneal folds into the rectovaginal septum (the tissue between the rectum and the vagina) which does not contain any other abdominal organs. An enterocele is a protrusion of peritoneal folds between the rectum and the vagina containing a loop of the small intestine. It is abnormal descent of the small bowel in a deep pouch of Douglas. A sigmoidocele is a protrusion of the peritoneum between the rectum and vagina that contains a loop of the sigmoid colon. An omentocele is a protrusion of the omentum between the rectum and the vagina. These conditions can additionally be described as internal (when visible only on defecography) or as external (when there is a rectocele or rectal prolapse which is visible without imaging). If these abnormalities do no reduce spontaneously, the term perineal hernia is used.

A peritoneocele usually originates in the posterior compartment of the pelvis, or sometimes it can be located anteriorly (in front) or laterally (on the side) to the vagina. In severe cases, during defecation peritoneal contents can protrude through into the vagina or rectum, or displace them. Symptoms are variable, depending on the severity and the location of the herniation, and may include incomplete evacuation of the rectum, heavy sensation in the pelvis, and constipation.

Enterocoele may develop because of weakening pelvic floor, multiple pregnancies, hysterectomy, and long term chronic straining. Sometimes people have a developmental condition where the rectovaginal septum fails to completely fuse, and they have a congenitally deep pouch of Douglas.

Psychological factors

Potential psychological factors which may contribute to ODS are anxiety, depression, post-traumatic stress and sexual abuse. For example, one-third of females with ODS and proctalgia have a history of sexual trauma during childhood or adolescence. Patients with ODS have a higher than normal level of psychiatric conditions, such as obsessive-compulsive disorder, phobia of stool, and eating disorders (such as anorexia nervosa or bulimia). Many patients with ODS will report initiating stressful life events that worsened their constipation. Such life stressors include new job, divorce, financial problems, sexual abuse or assault.

Diagnosis

Diagnosis is very challenging for clinicians, since most patients will simply complain of "constipation". As discussed previously, there are many possible causes of ODS, which often may occur together in the same patient, and ODS may co-exist with other conditions such as slow-transit constipation.

The two key features of obstructed defecation are:
# An inability to voluntarily evacuate rectal contents
# Normal colonic transit time

A five-item questionnaire was validated for diagnosis and grading of obstructed defecation syndrome. The parameters were:
# Excessive straining
# Incomplete rectal evacuation
# Use of enemas and/or laxatives
# Vaginal-anal-perineal digitations (needing to press in the back wall of the vagina or on the perineum to aid defecation)
# Abdominal discomfort and/or pain

Dyssynergic defecation

Dyssynergic defecation may be detected clinically, by digital rectal examination. Non relaxation or paradoxical contraction of the puborectalis muscle at the anorectal junction can be felt when the patient performs a Valsalva manoeuvre or evacuation. The diagnosis can be confirmed by anal electromyography, anorectal manometry, and/or defecography.

"Celes"

It is difficult to tell peritoneocele, enterocele and sigmoidocele apart from rectocele without imaging. Peritoneocele is the most difficult type of pelvic prolapse to detect by clinical examination. To improve visualization of peritoneocele during MR defecography, the patient should complete normal defecation and the rectal contrast material should be completely evacuated, because then the rectovaginal space widens and pushes the peritoneum and bowel loops inferiorly (lower).

An enterocoele can be easily detected by a clinician during physical examination. Using a bidigital technique (one finger in the anus and another in the vagina), the mass of the enterocele can be felt to "slip upwards" between the fingers when squeezing together. If the patient coughs during this procedure, it is easier to detect.

Classification

Obstructed defecation is one of the causes of chronic constipation.

Outlet obstruction can be classified into four groups.

* Functional outlet obstruction
:* Inefficient inhibition of the internal anal sphincter
::* Short-segment Hirschsprung's disease
::* Chagas disease
::* Hereditary internal sphincter myopathy
:* Inefficient relaxation of the striated pelvic floor muscles
::* Anismus (pelvic floor dyssynergia)
::* Multiple sclerosis
::* Spinal cord lesions

* Mechanical outlet obstruction
::* Internal intussusception
::* Enterocele

* Dissipation of force vector
::* Rectocele
::* Descending perineum
::* Rectal prolapse

* Impaired rectal sensitivity
::* Megarectum
::* Rectal hyposensitivity

Treatment

European consensus guidelines on management

In 2021 a consensus regarding approach to treatment of ODS was published. A panel of 31 surgeons from 12 European countries worked on the consensus. The members of the panel were all engaged in research and treatment of ODS, and were considered expert in the field of pelvic floor functional disorders. They came to a consensus on about 50% of controversial issues surrounding management of ODS, which enabled creation of a treatment algorithm. The algorithm was based around the condition of the function of the anal sphincter, the presence of dyssynergia and the presence of other abnormalities like rectocele, intussusception, etc.

They unanimously agreed that surgery should be discouraged for pelvic floor dyssynergia, and instead that biofeedback/pelvic floor retraining was the first line treatment. When dyssynergia is present with major abnormalities like rectocele or rectal intussusception, biofeedback/pelvic floor retraining should be conducted prior to surgery.

For patients with rectal intussusception and a large rectocele or enterocele the experts all preferred laparoscopic (transabdominal) ventral rectopexy with non resorbable mesh, regardless of the function of the sphincter. Especially in the case of poor sphincter function (e.g. some degree of fecal incontinence), they preferred to avoid transanal approach, because there is greater risk of further deterioration in continence function. In the event of failure of previous ventral rectopexy, the consensus was to repeat the same procedure again rather than carry out different procedures.

For patients with large rectocele or enterocele only (i.e. no intussusception), there was no clear consensus about the best treatment. The experts did however agree that mesh should not be used for direct rectocele repair.

Conservative (non-surgical)

Some authors state that treatment of ODS is mainly conservative. Many such conservative (non surgical / medical) measures have been used to treat ODS:
* Biofeedback, also termed (Pelvic floor rehabilitation).
* Dietary measures, especially high fiber diet.
* Bulking laxatives.
* Rectal irrigation.
* Transanal electrostimulation.
* Yoga.
* Psychotherapy.

Diet

Dietary measures are frequently used for ODS as the first line treatment. The aim is to improve stool texture. It has been recommended to avoid foods like chocolate, which increase stool viscosity, making it more difficult to pass stools. Bulk-forming laxatives are also frequently used for ODS.

It is recommended to increase dietary fiber intake to 25-30 grams daily. This may be slowly increased up to a level of 50 grams per day. This is usually achieved with high-fiber cereal and fiber powder supplements such as psyllium, methylcellulose, polycarbophil, or wheat dextrin. However, fibre supplementation only fractionally increases gut
transit and stool bulk. The effect may take several weeks to become apparent.

Patients with ODS are often advised to drink plenty of water. 1-2 liters of water per hour is recommended, especially in warmer climates or warmer weather.

Biofeedback / Pelvic floor rehabilitation

Biofeedback is a learning strategy which is based on operant conditioning. The main goal is to improve abdominal and pelvic floor coordination. Biofeedback can successfully treat abnormal contraction and relaxation of muscles in the anorectum during defecation. This enables normal peristalsis instead of abnormal contraction and retrograde of bowel contents.

Biofeedback is most beneficial for patients with dyssynergic defecation. It is also used for rectal hyposensation. Rectocele and recto-rectal intussusception can sometimes be treated by pelvic floor rehabilitation alone, as long as they have not been present for a long time. Larger and more significant examples of these organic/anatomical disorders require surgery to correct since they because contributing causes to ODS by themselves. Regardless, this treatment seems to be beneficial both for patients with mild symptoms, and for those with severe symptoms which are unresponsive to other conservative measures and who are being considered for surgery.

Biofeedback has been shown to improve symptoms (improved frequency of bowel movements, reduced straining) and also reduce need for laxatives, and patients stop needing to self-digitate. Researchers demonstrated that patients who had positive results with biofeedback had evidence of improved autonomic innervation of the colon, increased colonic transit time, and had increased quality of life scores.

For patients who do not undergo biofeedback, simple pelvic floor and abdominal muscle relaxation exercises may also be useful to make evacuation easier.

Psychotherapy / Psychological counselling

Psychological counselling is indicated for people with ODS and depression and/or anxiety. Psychological techniques (guided imagery and relaxation) have been combined with ultrasound-guided biofeedback. This "psycho-echo-biofeedback" approach was reported to be successful for 50% of patients after 2 years.

Irrigation

Variously termed hydrocolontherapy, lavage, retrograde large bowel irrigation, and rectal irrigation. This refers to the use of water to wash out the rectum. Usually this is done with warm water (or normal saline), administered via a tube inserted into the anus. Some authors report this treatment as effective and safe with no risk of side effects. Self-administered enemas may however be abused, which can cause anorectal fibrosis and stricture, due to repeated microtrauma. The disadvantages of this treatment are mainly social stigma and inconvenience. The water and stool may take some time to fully evacuate, especially with patients with obstructed defecation. People with reduced muscular strength of the anal sphincter may encounter problems with later leakage of the water mixed with stool, which may bring similar, socially devastating problems as seen with fecal incontinence. Overall this treatment may be dissatisfying to patients because of difficulty with cohabitation, travel, and work/study or leisure activities.

Transanal electrostimulation

Transanal electrostimulation is carried out at home with an anal probe and an electrostimulator. It is a treatment for pudendal nerve neuropathy and rectal hyposensation. Another new treatment combines biofeedback with transanal electrostimulation.

Botox injections

Injection of 50-60 units of botulinum toxin A into the puborectalis muscle has been reported for anismus, and ODS. The botulinum toxin is injected under ultrasound guidance into two sites on both sides of the puborectalis muscle. This procedure itself could be considered as minor surgery, although in the studies reporting this technique, patients were not sedated or given local anesthetic. Short term cure rate was approximately 50%. Another study reported 79% of patients had improved symptoms, and had broadening of the anorectal angle demonstrated on defecography. Side effects are transient anal incontinence and hypotension. The effects of Botox only last for about 3 months, meaning the procedure may only be temporary and it may have to be repeated.

Other measures

Anismus has been reported to be treated with yoga exercises.

Prognosis

ODS generally has a benign prognosis, however it is distressing condition for patients. The condition may severely reduce quality of life, both socially and psychologically. Symptoms persist for some patients despite conservative treatment, and dissatisfactory outcomes are frequently reported after surgery.

Epidemiology

ODS occurs in 7% of the adult population. Another source estimated that about 10–20% of adults have ODS. According to one report "evacuation disorders" are common, affecting 12–19% of North Americans. Most patients with ODS are females.

References

{{Digestive system and abdomen symptoms and signs

Symptoms and signs: Digestive system and abdomen
Defecation